A is for Alice and astronomers arguing about acceleration -- B is for Bernard's body-exchange machine -- C is for the Catholic cannibal -- D is for Maxwell's demon -- E is for evolution (and an embarrassing problem with it) -- F is for the forms lost forever to the prisoners of the cave -- G is for Galileo's gravitational balls -- H is for Hume's shades -- I is for the identity of indiscernibles -- J is for Henri Poincaré (...) and alternative geometries -- K is for the Kritik and Kant's kind of thought experiments -- L is for Lucretius' spear -- M is for Mach's motionless chain -- N is for Newton's bucket -- O is for Olbers' paradox -- P is for Parfit's person -- Q is for the questions raised by thought experiments quotidiennes -- R is for the rule-ruled room -- S is for Salvatius' ship, sailing along its own space-time line -- T is for the time-travelling twins -- U is for the universe, and Einstein's attempts to understand it -- V is for the vexed case of the violinist -- W is for Wittgenstein's beetle -- X is for xenophanes and thinking by examples -- Y is for counterfactuals and a backwards approach to history -- Z is for Zeno and the mysteries of infinity. (shrink)

Diversity is a good thing. Some of its value is instrumental. Having people around with diverse beliefs, or customs, or tastes, can expand our horizons and potentially raise to salience some potential true beliefs, useful customs or apt tastes. Even diversity of error can be useful. Seeing other people fall away from the true and the useful in distinctive ways can immunise us against similar errors. And there are a variety of pleasant interactions, not least philosophical exchange, that wouldn’t be (...) possible unless some kinds of diversity existed. Diversity may also have intrinsic value. It may be that a society with diverse views, customs and tastes is simply thereby a better society. But we will mostly focus on diversity’s instrumental value here. We think that what is true of these common types of diversity is also true of moral diversity. By moral diversity we mean not only diversity of moral views, though that is no doubt valuable, but diversity of moral behaviour. In a morally diverse society, at least some people will not conform as tightly to moral norms as others. In short, there will be some wrongdoers. To be sure, moral diversity has some costs, and too much of it is undoubtedly a bad thing. Having rapists and murderers adds to moral diversity (assuming, as we do, that most people are basically moral) but not in a way that is particularly valuable. Still, smaller amounts of moral diversity may be valuable, all things considered. It seems particularly clear that moral diversity within a subgroup has value, but sometimes society as a whole is better off for being morally diverse. Let us consider some examples. Many violations of etiquette are not moral transgressions. Eating asparagus spears with one’s fork is not sinful, just poor form. But more extreme violations may be sinful. Hurtful use of racial epithets, for example, is clearly immoral as well as a breach of etiquette. Even use of language that causes not hurt, but strong discomfort, may be morally wrong.. (shrink)